Many physicians will at some point care for patients who will receive life-sustaining treatment by default, because there are no instructions available from the patient as to what kind of care is preferred, and because surrogates are likely to ask for everything to be done when they do not know a patient's preferences. We use the methods of ethics informed by qualitative focus group research to identify 5 pathways to life-sustaining treatment by default originating with the patient's preferred decision-making style: deciding for oneself or letting others decide. We emphasize preventing the ethically unwelcome outcome of life-sustaining treatment by default by increasing the frequency with which patients make clear decisions or clearly express their values and goals that they then communicate to physicians or surrogates.